This specification relates generally to query refinement.
The Internet provides access to a wide variety of resources, for example, video files, image files, audio files, or Web pages including content for particular subjects, book articles, or news articles. A search system can select one or more resources in response to receiving a search query. A search query is data that a user submits to a search engine to satisfy the user's informational needs. The search queries are usually in the form of text, e.g., one or more query terms. The search system selects and scores resources based on their relevance to the search query and on their importance relative to other resources to provide search results that link to the selected resources. The search results are typically ordered according to the scores and presented according to this order.
Some search engines also provide a list of query suggestions along with the result listing for the original search query submitted by the user. The query suggestions are queries that are related to the original search query in terms of the subject matter that they represent. For example, each query suggestion may share one or more search terms with the original search query or belong to the same topical category as the original search query. Query suggestions can help the user focus their search toward one of several possible directions or find better expressions of the information he or she is interested in. Typically, the search engines rank the related search queries based on a number of factors and only a small set of top-ranked related queries are presented to the user as query suggestions.
For example, query suggestions for an original query submitted by a user can be derived from query logs of a multitude of users. Typically, search queries related to the original query are identified in the query logs based on one or more shared search terms in the original query and the related queries. The related queries are ranked based at least in part on their frequencies of occurrence in the query logs. Consequently, only the most popular queries are likely to be presented to the user as query suggestions. Sometimes, these query suggestions may not accurately reflect the specific interests of the user submitting the original search query.